% 严格按照作图的步骤绘制
\begin{tikzpicture}
    \tkzDefPoints{0/0/A, 4/0/B}
    \tkzDrawSegments[xianduan={below=0pt}](A,B)
    \tkzLabelPoints(A,B)

    % 1
    \tkzCalcLength(A,B)  \tkzGetLength{ab}
    \pgfmathsetmacro{\r}{0.6*\ab}
    \tkzInterCC[R](A,\r)(B,\r)  \tkzGetPoints{C}{D}
    \tkzCompasss(A,C  B,C  A,D  B,D)
    \tkzLabelPoints[right](C,D)

    % 2
    \tkzDrawLine[add=0.2 and 0.2](C,D)
\end{tikzpicture}

